Windows Vista has had its fair share of problems, a good few of those have been solved though some still linger around. Microsoft is preparing to release Vista SP1 next month which has been known to solve some of the existing problems but has created new ones. The company also introduced a feature in Vista called the anytime upgrade.
Say you arent happy with the version of Vista your PC shipped with, well, you can purchase the anytime upgrade. The only people that really benefit from this are Vista Basic users but even then a PC that shipped with Vista Basic cant run all of the features included in the better editions.
Most PCs ship with Vista (Home) Premium or Vista Business which can be upgraded to Vista Ultimate, your only choice with those operating systems. Some may think its worth the extra price to upgrade but its usually not. Premium, Business and Ultimate share so many features it can be hard to tell what youre missing out on.